Anoxic-ischaemic cell change in rat brain light microscopic and fine-structural observations

Excessive accumulation of hydrogen ions in the brain may play a pivotal role in initiating the necrosis seen in infarction and following hyperglycemic augmentation of ischemic brain damage. To examine possible mechanisms involved in hydrogen ion-induced necrosis, sequential structural changes in rat brain were examined following intracortical injection of sodium lactate solution (pH 4.5), as compared with injections at pH 7.3. Following pH 7.3 injection, neuronal swelling developed between 1 and 6 h, but only a needle track wound surrounded by a thin rim of necrotic neurons and vacuolated neuropil was present 24 h after injection. In contrast, pH 4.5 injection produced neuronal necrosis as soon as 1 h after injection, followed by necrosis of astrocytes and intravascular thrombi at 3 and 6 h. Alterations common to both groups included vascular permeability to horseradish peroxidase, dilation of extracellular spaces, astrocyte swelling, capillary compression, and vascular stasis. These data suggest that neurons, astrocytes, and endothelia can be directly damaged by increased acid in the interstitial space. Lethal injury initially appeared to affect neurons, while subsequent astrocyte necrosis and vascular occlusion may damage tissue by secondary ischemia.

Section: Discussionmentioning

confidence: 72%

Light and Electron Microscopic Evaluation of Hydrogen Ion-Induced Brain Necrosis

Petito

Kraig

Pulsinelli

1987

“…Nuclear changes of apoptosis were absent. Other studies examining the cerebral cortex or striatum in global ischemia also show that cytoplasmic changes precede nuclear changes and that the early nuclear changes of apoptotic cells are not present (Brown and Brierley, 1972;Dodson et aI., 1977;Ekstrom et ai., 1982;Petito and Pulsinelli, 1984a;Diet rich et ai., 1991).…”

Section: Discussionmentioning

confidence: 97%

DNA Fragmentation Follows Delayed Neuronal Death in CA1 Neurons Exposed to Transient Global Ischemia in the Rat

Petito

Torres-Muñoz

Roberts

et al. 1997

143

Summary: Apoptosis is an active, gene-directed process of cell death in which early fragmentation of nuclear DNA pre cedes morphological changes in the nucleus and, later, in the cytoplasm, In ischemia, biochemical studies have detected oli gonucleosomes of apoptosis whereas sequential morphological studies show changes consistent with necrosis rather than ap optosis, To resolve this apparent discrepancy, we subjected rats to 10 minutes of transient forebrain ischemia followed by I to 14 days of reperfusion, Parameters evaluated in the CAl region of the hippocampus included morphology, in situ end labeling (ISEL) of fr'l-gmented DNA, and expression of p53, Neurons were indistinguishable from controls at postischemic day I but displayed cytoplasmic basophilia or focal condensations at day 2; some neurons were slightly swollen and a few appearedThe neuronal response to brain ischemia depends on the severity and duration of the ischemic insult as well as on intrinsic neuronal factors that impart selective vulner ability to specific brain regions (Scholz, 1953), Brief periods of global ischemia kill vulnerable neurons in the CAl region of the hippocampus whereas longer intervals of vascular occlusion kill neurons in the cerebral cortex and corpus striatum as well (Ito et aI., 1975; Pulsinelli et aI., 1982a), Although seemingly undamaged, neurons in other brain regions such as the CA3 region of the hip pocampus or the paramedian cerebral cortex undergo transient alterations as evidenced by reversible changes 967normaL In situ end labeling was absent At days 3 and 5, approximately 40 to 60% of CAl neurons had shrunken eosin ophilic cytoplasm and pyknotic nuclei, but only half of these were ISEL By day 14, many of the necrotic neurons had been removed by phagocytes; those remaining retained mild ISEL Neither p53 protein nor mRNA were identified in control or postischemic brain by in situ hybridization with riboprobes or by northern blot analysis, These results show that DNA frag mentation occurs after the development of delayed neuronal death in CA I neurons subjected to 10 minutes of global isch emia, They suggest that mechanisms other than apoptosis may mediate the irreversible changes in the CAl neurons in this model. Key Words: Global ischemia-Apoptosis Necrosis-Delayed neuronal death-In situ end labeling-Rat in their subcellular organelles (Petito and Pulsinelli, 1984a,b), The postischemic interval required for the ap parent development of selective neuronal necrosis is in versely proportional to the severity or duration of the ischemic insult-the so-called maturation phenomena described by Ito et al. (Ito et at, 1975), This interval is especially prolonged in the CAl neurons of the hippo campus (Ito et aI., 1975; Pulsinelli et aI, 1982a). The term delayed neuronal death has been applied to this process (Kirino, 1982).During the past few years, the concept of cell death via apoptosis has become increasingly important. This mechanism of cell death is mediated by regulated path ways involving defined gene product...

“…The criteria for neuronal damage were those of Brown and Brierley (1972) and Salford et al (1973). These included microvacuolation (microvacuoles appear as ap parently empty circular or oral spaces within a strongly basophilic cytoplasma); ischemic cell change (shrunken nucleus, often triangular and darkly staining so that the nucleus is sometimes difficult to distinguish, cell body shrunken with loss of Nissl substance, cytoplasm acido philic and stained pink with eosin); and ischemic cell change with incrustations (neuron resembles above but there are also heavily stained incrustations on the surface of the cell bodies and sometimes on the dendrites).…”

Section: Methodsmentioning

confidence: 99%

Local Cerebral Glucose Utilization in Chronic Middle Cerebral Artery Occlusion in the Cat

Komatsumoto

Greenberg²,

Hickey

et al. 1989

Summary: This study examines the correlation between local CMRglc (LCMRglc) alterations and clinicopatholog ical changes in a chronic middle cerebral artery (MCA) occlusion model in the cat. The left MCA was occluded for a period of 2 h. The animals were grouped into mild, moderate, and severe ischemia based on the depression of the EEG 30 min after the MCA occlusion. Follow ing release of the clip, the animals were allowed to re cover for a week during which time daily neurological examinations were performed. On the seventh day P4C]2-deoxyglucose was injected for the determination of LCMRglc• Alternative blocks were processed for histo logical evaluation in which both neuronal and phagocytic changes were graded into four categories (0 = normal to 3 = severe). LCMRglc (J.LmollIOO glmin) in the ischemic hemisphere (all histological grades) was significantly lower than the metabolic rate in comparable regions of the sham MCA occlusion group. Regions with significant phagocytosis (grade 2 and 3) invariably exhibited acti vated glucose metabolism (57.4 ± 8.4 and 105.9 ± 6.8 J.Lmol/lOO glmin, respectively), which was significantlyThe recovery process of brain tissue after an isch emic insult may be closely related to its metabolic state. Although the recent development of positron emission tomography has offered the potential for investigating glucose metabolism of the human brain Phelps et al., 1982), few studies have been made early following a stroke (Kuhl et al., 1980;Lenzi et al., 1982;Wise et al., 1983;Baron et al., 1984;Kushner et al., 1987). These findings provided some information about Abbreviations used: 2-DG, 2-deoxyglucose; LC, lumped con stant; LCMRgl c, local CMRglc; MCA, middle cerebral artery. 535higher than in regions without phagocytosis (30.4 ± 0.8 J.LmolllOO g/min). There was a significant gradient of me tabolism in the central, peripheral, and boundary zone and the non-MCA territory in the animals with severe ischemic lesions. LCMRglc in the central MCA territory was well correlated with the EEG amplitude changes (r = 0.82, p < 0.05) and the morphological score (r = -0.89, p < 0.05). The metabolic rate was significantly depressed in both the ipsilateral and the contralateral central MCA territories in comparison with the sham occlusion ani mals. The depression in LCMRglc in the contralateral hemisphere correlated well with the concomitant depres sion in the contralateral EEG amplitude. These studies demonstrate that local heterogeneous metabolic alter ations and contralateral cortical diaschisis exist chroni cally following temporary MCA occlusion and that the increases in local cerebral glucose metabolism seen in chronic stroke may be due to phagocytotic activity.